Rudder for boats



5, 1945- A. J. DAWSON 2,383,714

RUDDER FOB BOATS Filed July 7; 1945 3 Sheets-Sheet l INVENTOR .Albert JlJaws an dam- Aug. 28, 1945.

A J. DAWSON RUDDER FOR BOATS 3 Sheets-Sheet 2 Filed July '7, 1945 Au 28, 1945. A. J. DAWSbN 2,383,714

RUDDER FOR BOATS Filed July 7, 1943 3 Sheets-Sheet 3 I I i 1 l g INVENTOR and consists in improvement boat is rendered more tiller, particularly in backing.

Patented Aug. 28, 1945 I oissie RUDD ER FORI BOATS' Albert J.- Dawson, Pittsburgh,-,,Pagmassignor to Dravo Corporation, Pittsburgh, Pa., a corpora tion of Pennsylvania Ap lication July 7, 194a; series-Norway This invention relates to the steering of boats upon steering appa- Ko'rt nozzle," whereby the readily responsive to her ratus that includes a The invention-is illustrated in the accompanying. drawings, in which! I Figure I is. axview in vertical and- 7 medial section of the steerina equipment of-the invention in assembly upon the stern ofa boat;

Figure II is a view of the steering equipment in" elevation, as seenzfromxastern and looking forward';:-

Figure III is a lview-zin horizontal. section; on the: plane-indicated by Figure II;-

Figure-JV isan-sectionaliviewy'partly on the horizontal plane iaxial of the.-:1propeller -'shaft, partlyv 1011 higher plane; and illustrates the ranges of: swingof components of i the: equipment FigureV is a fragmentary view, in-rhorizonta'l section, onwthe plane -V-'V\of Figure "I;

Figureis 'a top :plan :-view a ship withtherud-derassembly; and

Figure VII. Sis a-viewxsimila'r ;to'-Fi'g,ure I, of a modified'construction'.1

In the propulsion of boats it is=a;known expedient Ito-enhance.the-efiectpof apropeller; and,

, incidentally, to shield'andprotect ityby encircling it within a ring properly shaped and proportioned; Such van encircling-ring is shown and described: '-in.Un-ited :States Letters. Patent 'No. 2,030,375; granted to L. Kort; The ring; is gulletlike-leand flares forwardly and rearwardly {from a medial-portion-of minimum diameter; and-,-in

cross-sectional: shape-the ring-s walls are of streamlined or hydroioil;-contour.-. The-ring is so assembled with the propeller that the plane in which the :tips of the propeller blades rotate is substantially coincident with 'the-;vertical. diameter of'the circle of .thelrin'g -wall at its narrowest.- Sucharing iseknownxto thei =industry as a Kort nozzle? 113x13 also a known expedient to mount' such a propellenencircling, ring upon the rudderof, the

boat, and so to give to'it additional functional value, aspart of the steeringapparatusp -Such an arrangement is illustrated in: Letters Patent No. 899,359,,granted to Y; Wadagaki, Itis upon such an organization-what the present improve ment is made.,--

Referring to the drawings; apintle-hungrudder 1, having a Kort nozzle 2 integrated :withit,

is-shown-to be-mounted upon the-stemcot a boat B. The rudder. is so built-that the axis-of: turnof the-stern oi ing 'of the rudder is coincident with:th-e: vertical minimum internal diameter of the nozzle; and is so assembled that this axis oi-turnirig is COill'C'iedent with the plane in-which the tips of the Propeller blades rotate.= The rudder is shown to be" joverhungi from: the transom or stem of the boatiitmight be hung from a false, transom recessed withinthe sternl. A beari'ng-block 3 for *theprcpeller shaft 8 is carried 'on a strut 4' that extends downward-from the=overhangvof tHe-stern.-1. This strut, in :accommodation 'to' the further features :of'inverrtion; is formed of two symmetrically shapedazout wardl-y' bowed plates that: converge sternwam to an e'dgeA as clearly seen in Figures IV- and ,V. A-t the forward edge-of strut l an auxiliary rudder-5, carried under the overhang of the-boat, Y

is mounted to swing. one vertical axis; i. ve. perpendicul'ar tothe-axisofzth'e propeller shaft; and, as appears in'Figure IV; the. axis 10f swing'ofqthe auxiliary-rudder 5 is like the axis of swing. of themain rudder-I, coincident with'the: vertical plane: through the axis-of propeller rotation.-: The auxiliary "rudderrS rextends forwardly 1 from its axis of pivoting, and beneath the overhang-"of thesterrr of the-boat: Ituis' of'forwardly taperingvshapewas best seen in-Figure V, and; when in "IInd-JDOsitiOn (Fi'gure"-'V) it formswithnthe strut 14' -a structure of streamlined, hydrofoil shapeu Thev sternward taperof the plates-that form the strut is more abrupt than the gradual forward :taperofthe boclyoi the rudder 5 itself.

The auxiliary rudder 5 ismounted upon a post Bnand the postG lrests inandtis rotatably; borne 4', isarranged .to. extendimmedi'atelyforward of theuintake end'rmforwardend) of the-nozzle 2, with. sufilcient clearance, however, to allow the nozzletovswing. in horizontal plane throughout its propenrange of turning, I

. The auxiliary rudder-vii isrsobuilt and organized asto bewcapable of;

swinging in unison with the swing of the main rudder I. Each steering unituhasuits proper range+itsxzproper:steering angle-and; the proper rangeiof swingof the-iauxchannels. Y 1

iliary rudder is greater-approximately fifty per cent greater-than that of the unit comprising rudder l and nozzle 2. Of the latter, the proper range of swing is approximately 22 to either side from fore-and-aft position; of the auxiliary rudder the proper range is approximately 33. This I is indicated in Figure IV by the arcs a and 1). Linkage is provided, as indicated at l, and best shown in Figure VI, connecting the two rudder units I, 2 and 5, such that, while unit I, 2 swings through an angular range of 2m, unit 5 swings through a range of 3m, and further, that the units shall have permissible ranges of swing respectively through their proper ranges. The links I are connected at their forward ends 'to opposite endsof member Go on the rudder post 6 and the rear ends are pivotally connected to combined with a single propeller- P, and all arranged on the center line of the ship. It will be propeller, a rudder element forwardly of the noza plate member 1a at the top of the rudderl, a

and the differential movement is accomplished by reason of the rear ends of the links 1 being further from the center of rotation ofthe plate Ia'than are the forward ends of the-link "I from the axis of rotation of 'post 6. I

, It is not necessary that the stern end of the auxiliary rudder (formed by the strut '4) be movable; by its rigidity it serves other useful ends; and it suffices that the forwardly; extending. portion 5 swing, to aidin steering.

In the forward travel of a boat equipped with the steering apparatus described, theaction of i the auxiliary rudder 5 tendsito render the boat more immediately responsive-to her helm; it is in backing, however, that the utilityof the unvention is greatest, When the propeller begins to turn backward, the'Kort nozzle isof relatively small effect as a steering element, and (lacking ginning of backward movement is immediate and pronounced, and the boat responds accordingly. In consequence, the steering equipment of the invention is of peculiar value and advantage in the navigation of rivers and narrow and winding The construction shown in Figure VII is essentially the same as that shown in FigureI, except ,that'the auxiliary rudder 5 has a counterpart 5a below the propeller shaft, and, accordingly, corresponding reference numerals are used to indi- To provide the lower cate corresponding parts. auxiliaryrudder section, a portion 4a, conforming'generally in contour to part 4, projects down the auxiliary rudder of the invention) the boat from the bearing 3 and it has two forwardly prov v jecting'lugs 9 and H1. The upper lug llhas a depending pin H thereon that enters the top of portion 52) or the rear of the rudder sectioniia. A removable pin i2, held in placeby nut l3,projects through the lower lug in into a lug 50 on the rudder section EafBy removing nut l3, pin I2 may be dropped down, whereupon rudder section 5a may be lowered until part 51) is free of pin I I, thus enablingthe'rudder section 5a to be quicklyremoved. Outwardly bowed straps l4, bolted to sections 5 and 5a on each side face of the rudder,-transmit turning motion from the upper to the lower section, while the outward bowing of the straps givesclearance for the propeller shaft,

so that the arc of movement of the rudder'55a The straps may be is not confined by the straps. in line with the rudder post, but for clearness of illustration they are shown forwardly of the rudzle, said rudder element being plvotally supported at the aft end thereof, and means differentially coupling the rudder and the nozzle for concomitant operation through differing degrees of are.

. on a fixed rudder section with its pivotal axis adjacent the fixed rudder section, said fixed rudder section being immediately forward of the nozzle and of 'a-shape which complements the streamline of the rudder, and means operatively connecting said movable rudder element'and the nozzle. 1- o 3. In a ship propulsion and steering mechanism having a propeller shaft and propeller and having a nozzle element surrounding the propeller, said nozzle being movable about an. axis substantially perpendicular to the axis of rotation of the propeller; a movable rudder element forwardly 'of the nozzle symmetrically disposed above and below the propeller shaft, said rudder 'element being pivotally supported at the aft end thereof for movement about an axis, substantially perpendicular to the axis of rotation of the propeller, and means differentially coupling the rudder and the nozzle for concomitant operation through different degrees of arc with 'therudder element having an arcuate' movement greater than the nozzle. u

4. Steering apparatus for a boat wherein there is a nozzle encircling the propeller of the boat, the nozzle being movable in an arc about avertical axis, the herein described invention comprising an auxiliary rudder arranged forward of said nozzle and pivoted at its stern end for move ment about a vertical axis, and means interconnecting the nozzle'an'd the auxiliary rudder for turning them simultaneously in the same effective direction and to different degrees of are;

5. Steering apparatus for a boat with overhanging stern and a propeller shaft extending beneath such overhang, and in combination with a rudder unit than includes a nozzle adapted to encircle a propeller borne by such shaft, the invention herein described which consists of a'strut dependingfrom such overhang and forward of said nozzle, a bearing block for the propeller shaft borne by said strut, and an auxiliary rudder mounted for turning upon an axis adjacent the forward'edge of said strutand extending thence forwardly, the auxiliary. rudder being in the stream flowfrom' the-nozzle when the propeller 2,sss,714

the forward edge of said strut and extending thence forwardly, the strut being of sternward tapering horizontal section, the auxiliary rudder being a forwardly tapering horizontal section, the

two last named members forming a unit of hydrofoil shape in horizontal section.

ALBERT J. DAWSON. 

